Web extrusion die



Feb. 17, 1953 H. T. TORNBERG 2,628,386

WEB EXTRUSION DIE Filed April 29, 1952 2 SHEETS-SHEET l Feb. 17, 1953 H. T. 'roRNBERG was ExTRusIoN DIE 2 SHEETS-SHEET 2 Filed April 29, 1952 k for/32 www TEM/55e@ VEA/70E Patented Feb. 17, 1953 UNITED STATES TENT OFFICE VVILBr EXTRUSION DIE- a corporation of Delaware,

Application April 29, 1952;SerialN'o. .284;991

(Cl. 1l8.12)y

6 Claims. 1.

The present inventionrelatesto plastic yextruding machinery and more particularly to a die construction for the extrusion of a web.

The die is an elongated structure having a passage therethrough for the plasticized material fed4 to it by the extruder., The entrance to such passage is a central opening in a wall of the die and the exit of said passage is a long and narrow discharge orifice. In practice. at least two oppositeV walls of this passage are divergent from the entrance opening, s o that theV material in its flow through thedie,:spreadsto web width which is the length of the discharge orice. The latter being along a straightlinethe distance for the stuff to travel through the die increases as thn point of discharge is` nearer the ends of the discharge orifice. Provision is made to adjust for web thickness and adjustment is also provided to attain uniformity ofweb thickness.

The flow of plasticized material through the central portion of the` discharge orice and its adjustment presents no diiculty, but the stuff flowing along the divergent die passage walls, due to thelonger interval it remains in the die, too often becomes burnt, adheres to said walls, clogs the passage at such regions and thereby causes the web. edges to be irregular. This especially occurs when the web is of lm thickness.

It is therefore oneof theobjects of this invention to provide a` dieof thetype set forth, of novel and improvedA construction which avoids such. objectionable condition by affording properly positioned and effective cooling ducts for the control of temperature along said divergent walls of the die passage.

Another object hereof is to provide a die of thei character set forth, of novel and improved construction, made up of'plates and bars, some of which when changed, adapt the die for the extrusion of webs of different widths, selectively.

A further object hereof is to provide a novel, simple and improved die of the kind described, which is relatively cheap,v tomanufacture, easy to manipulate to accomplish'various adjustments replacements, and eiicient` incarrying out the purposes for which it is designedfl Cther objects and advantages-Will become apparent as this disclosure proceeds.`

in the. accompanying drawings forming part of thisspeciication, similarcharacters vof reference indicatecorresponding parts-in all theviews.

Fig. l is-.a perspective .viewof anextrusion die embodying the teachings of this invention.

Fig. 2 is a section taken at lines 2-2 in Fig. l.

Fig. 3 is a fragmentary section taken at lines 3-3 in Fig. 1.

2. Fig. 4- isa,y perspectiveview of the-rback plate of said diepstructure..

Fig; 5.is a perspective'.viewfofy the spacer parts` which lie betweenthefront:andback platesfsuch parts being shown in their relative position in.

the-assembly;y

Fig. 6 is a perspective view-ointhe-.front plate. Eig. 7 is a,perspective:v viewoff thebarwhich is adjustablyr` positionable' to: set.: thea thickness` of web to belextrude'd.-

Fig. 8 is a perspectiva-viewofabar'xed to` the front, platewhen mountedz. This bar; carries certain adjustment-screws shownl in the'v assernbly for shifting the` bar-shown in Fig. v7;

Fig.' 9 is aperspective view of a' bar which serves as ai shelifforholding; theY 'bar' of Fig. 7'

and isused for having aes'eriesof setA screws to hoidfsaid bar of Fig.- 'Zin a 'set position.

Fig. l)A shows a'fragment.o'f'- attened tubingV whichV maybe used asa duct-for the passage of i cooling liquids,y as A'will' bei explained.

inthe drawings, thezdegindicatedgenerallyf by.v

the' numeral I5; comprises atspacer.l made up `of threev separate:parts-IE,1 IFI",v I8, between aafront plate I 9 and a; bfackfplate L29. Thefspacer part' I l mayhavegpins-Zi, spaced thereaiong and extend-.-Y

ing 1 lateraily 4 from :one1face: thereof'to be' removablyreceived inthesocketfhol'es 22:'in the hack plate. Bolts '2t-hold all of said* cornponentsin'A assembly. Thesegbolts are through` the counter-V bored holes 2^4fin-the rontfplatef' I8; the holes-Z5 in the spacer parts I6 and I81; and'ithe threaded holes -2'6 -in-,thefbaclt plata 2Q. Lengthwise along the 'underside' offthe `frontplate I8 and incontact' therewith, are the ftwo bars." 211s and f 2`8 which are ciV equal heightgfthe latterfbeingffreeto'.slide on a shelf providediby the: bar 29' 'beneath it: The oars @land .'29, areF secured'to` thefron't plate by meansofthebolts 353:: The-:shelf'bar 29"has^a' series of set screws 3l therealong to secur'ethe:

laterallyL adjustable: bari i282 whichrisf always spacedV iromtheibacloplate:2.0;:to forml the dis- Charge OICEl ini width;A The hea-'ds ofv` thesel set screws-.131 vare offc.ourso-@belowvv the shelf bary in` whichthey-'arethreaded ThebarfZ'I hasa series of adjustment screws-.32, respectively@positioned" 'between f the:y screwsi 3B? Theheads`r off said" ad` Alternate adj ustznentfsc'rews'Biare through clear holes in the oar 27 and in thieadedsocketsfin the The set Screws 3| are in the planes respectively of the adjustment screws 32.

The spacer part I1 is made very narrow and is substantially V-shaped in form. Its arms extend to the sides of the die and their free ends are formed to extend parallel; the distance between such parallel portions I1', determining the width of the web to4 be extruded. At the vertex between such arms, the back plate 20 has a'n opening 33 therethrough which serves as the entrance to the dies passage 40 formed by the front and back plates I9, 20 as one pair of opposite walls, and the divergent walls I1" as the other pair of opposite walls. Said entrance opening 3-3 is connected to the extruders discharge port by means for instance of a flanged pipe 34 which is secured to the back plate 20 by means of bolts through the threaded holes 35.

The portions I1 of the spacer part I1, extend to the bottom edge of the back plate 20. The adjustable blade or bar 28, just lits between said portions I1' and between the rearward end blocks 36 on the fixed front bar 21. The rear surfaces of these end blocks, contact the spacer portions I1 respectively; the bottom surface of the back plate 20, being in the plane of the bottom surface of the adjustable bar 28.

The die is adaptable for the extrusion of webs of diierent widths respectively, by having available replacements for the parts I1, 28, 21 and 36, of appropriate dimension.

The spacer parts I6 and I 8 are identical and have the spacer part I1 between them and are spaced therefrom in order to form in the assembly, the ducts 4| and 4.2 through which air or other cooling media may be forced into duct entrances 4I' at the sides of the die structure I5, leaving at the exits 4I" and 42". If desired, flattened tubing of the type 43 shown in Fig. 10, may be placed in each of said ducts, with its ends extending from the die structure at the mentioned entrances and exits for use as a passage for the cooling agent. Or else, when such tubing is directly on the arms of the spacer I1, spacer parts I6 and I8 may be omitted. In any event, the distance the cooling agent works through to eiect the plasticized materials in the space between the arms of the spacer member I1, should be indeed very short in comparison to the long length of said arms. The numerals 44 denote electric heater units carried on the die structure as is common practice.

The die illustrated is easily made at a relatively cheap cost out of standard bar and plate stock. BesidesV drilling and tapping, no other machining operations are required except to bevel the edge 28' of the adjustable bar 28.

The control of the temperature along the surfaces I1", affords proper and unspoiled web extrusion.

This invention is capable of various forms and applications without departing from the essential features herein disclosed. It is therefore intended and desired that the embodiment shown herein shall be deemed illustrative and not restrictive and that the patent sllall cover all patentable novelty herein set forth; reference being had to the following claims rather than to the specific description herein to indicate the scope of this invention.

I claim:

l. A web extrusion die comprising a pair of opposite plate components, a V-shaped spacer component positioned between and in contact with each of said plates along a V-shaped lane respectively; oneof said components having an opening at the vertex region of said V-shaped spacer for the introduction of a constant flow of plasticized material between the arms of said spacer and duct means along the arms of said spacer i'or the passage of a cooling agent directly lengthwise along the arms oi' said spacer; said duct means having openings outside the space between the arms of said spacer, for the entrance and exit of such cooling agent; the length of each of the arms of the spacer being comparatively large in relation to substantially all distances between the passageway for the cooling agent and the space between the said arms for flowing plasticized material.

2. A web extrusion die as dened in claim 1, wherein said openings for the cooling agent are near both ends of each of the arms of said V- shaped spacer.

3. A web extrusion die as dened in claim 1, wherein the means forming the duct comprise spacer means mounted between the plates outside the space between the arms of the V-shaped spacer, said arms and plates.

4. A web extrusion die as dened in claim 1, wherein the duct is aiorded by tube structure positioned along and in contact with each of the arms of the V-shaped spacer.

5. A web extrusion die as dened in claim 1, 'wherein the inner opposite surfaces of the remote free end portions of the arms of the V- shaped spacer are parallel; the distance between said surfaces at said free end portions, determining the width of the web to be extruded from the die; said free end portions of the arms being in Contact with one of the plates and extending beyond the second plate in the plane of the spacer; said second plate extending from the vertex region of the said V-shaped spacer a lesser distance than the rst plate, a bar having some resilient quality extending between and in contact with said opposite parallel surfaces and supported in Contact with the edge of the second plate toward which the arms of said spacer diverge; said bar being spaced from the rst plate and capable of lateral movement between said free end portions and screw means carried on the second plate at a series of points along said bar. to adjust the space between said bar and the lirst plate for determining the thickness of the web to be extruded from the die.

6. A web extrusion die as dei-ined in claim 5, wherein the plates, spacer and bar are separable whereby diierent spacers and corresponding bars may be selectively associated with the plates and means to detachably hold said plates and spacer in assembly.

HENNING T. TORNBERG.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,717,620 Page June 18, 1929 2,297,645 Bailey Sept. 29, 1942 2,387,718 Coleman Oct. 30. 1945 

